Begun in 1996 and initially funded by the Director's discretionary funds, the DNA Sequencing Shared Resource provides fast, on-site sequencing services to Moores UCSD Cancer Center Members. Eighty-six per cent of the utilization of this Shared Resource is from Cancer Center members while CCSG support for this Resource accounts for 30% of the Resource's annual operating expenses. Support of this Resource by the CCSG provides very cost effective DNA sequencing services to Cancer Center Members. The Resouce has developed a campus-wide reputation for providing consistently high quality, fast, long-read (1000+) and inexpensive DNA sequencing services. SNP analyses and microsatellite sizing for genome research or other applications is provided through the use of GeneScan, Genotyper and GeneMapper software used with our two Applied Biosystems 3130xl Genetic Analyzers. The speedy, convenient service established by this Resource for its users is complemented by the ready availability of expert consultation on how to solve difficult sequencing problems, relating to particular runs of bases in some parts of the genome. Such advice and help is a special value-added feature this facility provides for Center investigators, which is not easily obtained commercially. Our services have been designed to maximize efficiency for the investigator. Investigators use our web site to register their orders and define their template names. The Resource provides a daily courier service to pick up in each lab primers and templates ready for sequencing. Sequencing data is returned electronically within a turnaround time of 24 to 48 hours.